1. Field of the Invention
The present invention relates to an injector of a sperm for artificial insemination or a fertilized ovum for transplantation of a domestic animal such as cattle and the like and a method of operation therefor.
2. Description of the Related Art
Semen of so-called bull used for an artificial insemination is extremely valuable and expensive and is conserved in freezing state in an elongate sealed tube called a straw and is thawed at the time of artificial insemination when using. As an operation of injection of this semen into a uterus of a cow, a rectovaginal method has been generally used.
An operation of injection of semen of an ox by the rectovaginal method is described below referring to FIG. 10. FIG. 10 shows a cross section of a part of a uterus of a cow and reference numeral 1 denotes a rectum of a cow; 2 denotes a narrow and hourglass figure cervical canal positioned at an inlet of a uterus; 3 denotes a corpus uteri positioned at the back of the cervical canal; 4 denotes a pair of cornu uteri which is bifurcated from inner part of corpus uteri 3 and which are curved hemispherically.
A conventional injector of semen comprises an elongated narrow pipe 5 of small diameter, an injection tube 6 screwed to the front end of the pipe 5 and having a semen discharge opening perforated at the front end thereof, and a push bar 7 which is slidably inserted into a rear end of the pipe 5. A straw is provided inside the injection tube 6 in such a manner that a front end of the push bar 7 is to be inserted into the rear end of the straw to push and carry a cotton plug in the straw.
In injection operation, one hand is first inserted into a rectum 1 through an anus to grasp the cervical canal 2, then the rear end of the pipe 5 of small diameter is grasped and pushed by the other hand to insert the front end of the pipe 5 into a uterus. Then, the front end of the pipe 5 is penetrated through the cervical canal 2 while ascertaining the position of the front end of the pipe 5 by feeling of the one hand at a position of the cervical canal 2, and the front end of the pipe 5 is stopped short of reaching a cornu uteri 4. Thereafter, by pushing forward the push bar 7 exposed outside from the rear end of the pipe 5, a cotton plug in the rear end of the straw is pushed forward, thereby discharging semen in the straw from the semen discharge opening of the injection tube 6 into the uterus.
As a transplanter of a fertilized ovum for a cow, what is described in Japanese Examined Patent Publication No.61-36935 is publicly known. This transplanter is constructed by placing an inner pipe slidably in an outer pipe, the inner pipe having a front end which is rounded and sealed and being perforated with a small hole in a side of the end. This transplanter is also constructed so that a flexible tube inserted inside of the inner pipe may project through the aforementioned small hole.
When using, a fertilized ovum which is conserved by freezing in a straw is thawed, which is then sucked from the straw into a rear end of the flexible tube by using an attachment, and a syringe is fitted to the rear end of the tube. At the time when the outer pipe of this transplanter is inserted in a uterus of a cow, the small hole formed in the side of the front end of the inner pipe is covered with the outer pipe. Under this situation, the outer pipe is inserted into an inlet of cornu uteri in corpus uteri, and then the outer pipe is moved backward relative to the inner pipe to expose the small hole formed in the side of the front end of the inner pipe. Thereafter, the flexible tube is paid out forward from the back to project the front end of the tube outward through the small hole of the inner pipe so that the front end of this tube can reach to the depths of the uterus. Under this situation, air is supplied in the tube by operating a syringe, thereby injecting the fertilized ovum into the depths of cornu uteri from the front end of the tube.
However, since the pipe of small diameter in the aforementioned semen injector can only be inserted to stop short of reaching a cornu uteri, insemination rate has been relatively low.
It is possible to inject a fertilized ovum into the depths of uterus in the latter transplanter of fertilized ovum. However, since it is in double pipe construction comprising an outer pipe and an inner pipe, the outer pipe becomes thick having relatively large outer diameter. Therefore, when the outer pipe is inserted through a cervical uteri, there have been problems that insertion is relatively difficult and simultaneously endometrium might be injured.
Further, since there is a limit to enlarge the inner diameter of the inner pipe, the tube to be inserted therein is too narrow and weak to lead into the depths of cornu uteri certainly.
Furthermore, since it is not possible in the latter transplanter to confirm from the outside whether or not the opening of the small hole formed in the side of the front end of the inner pipe faces properly downward, there is a case where the small hole does not face downward because its position is shifted after insertion. In this case, the tube projected through the small hole is not inserted properly into the depths of cornu uteri. When the small hole faces upward, there is a case where the tube comes to contact with upper wall of corpus uteri and it returns to the inlet side. Therefore, the operation of the transplanter of the prior art has been very difficult.
Further, when this kind of operation is carried out outdoors in the cold latitudes, especially in case of the latter transplanter, since a fertilized ovum sucked into the tube from the thawed straw is exposed directly to the air in long-distance through the tube, there has been a risk that the fertilized ovum is shocked by temperature to be inactivated.
The present invention has been achieved taking the aforementioned problems into consideration.
Therefore, a first object of the present invention is to provide an injector of a sperm for artificial insemination or a fertilized ovum for transplantation of a domestic animal such as cattle and the like which can inject surely semen or a fertilized ovum into the depths of cornu uteri without injuring endometrium.
A second object of the present invention is to provide an injector of a sperm for artificial insemination or a fertilized ovum for transplantation of a domestic animal which is excellent in operability and can relieve temperature shock even when the operation of insertion of semen or a fertilized ovum into a uterus is carried out outdoors in the cold latitudes and a method of operating therefor.
In order to achieve the above-described objects, an injector of a sperm for artificial insemination or a fertilized ovum for transplantation of a domestic animal of the present invention comprises an outer pipe, a flexible tube inserted and placed inside of the outer pipe to be freely pushed out, a nozzle body mounted integrally to a front end of the flexible tube, the nozzle body having a closed front end which is formed in a shape of spherical surface and having a rear end connected to the flexible tube, the nozzle body further having in a side of the nozzle a perforated hole connected to the flexible tube, and a pushing means adapted to be connected with a rear end of the flexible tube for sending forward the sperm or ovum, the flexible tube being pushed forward from the rear end of the outer pipe after insertion of the outer pipe into a corpus uteri of the domestic animal, thereby paying out the flexible tube forward from the front end of the outer pipe to send nozzle body to a deep portion of a cornu uteri and thereafter to discharge the sperm or ovum from the perforated hole of the nozzle body into the deep portion of the cornu uteri through inside of the flexible tube by the pushing means.
Preferably, the flexible tube extends outside beyond the rear end of the outer pipe, the extended part of the flexible tube allowing to be pinched by finger tips and pushed forward by the finger tips.
Preferably, a heat-retaining tube is fitted to an outer peripheral surface of the rear end of the outer pipe, and the rear end of the flexible tube extends rearward from the rear end of the outer pipe and goes into the heat-retaining tube from the front end of the heat-retaining tube by making approximately one turn between the outer pipe and the heat-retaining tube.
Preferably, the one turn of the flexible tube defines a length of the flexible tube to be paid out from the front end of the outer pipe, the length of the flexible tube corresponding to the distance from the inside of the cervical canal to the deep portion of the cornu uteri.
Preferably, the injector further comprises a straw containing a sperm or ovum and removably attached between the rear end of the flexible tube and the pushing means to be contained in the heat-retaining tube.
More preferably, the heat-retaining tube is made from a transparent material.
Preferably, socket members adaptable to straws of different calibers is mounted removably to the front end and rear end of the straw respectively, and the straw is joined to the flexible tube and the pushing means respectively through each socket member.
Preferably, an effective substance for maintaining activity of a sperm or an ovum is previously injected into the pushing means before the straw is joined thereto.
Also, according to the present invention, a method of operating an injector set forth above is provided, wherein an outer periphery of the outer pipe is covered with a first plastic bag which is watertight, transparent and thin and the front end of which is sealed, an outer periphery of the heat-retaining tube is covered with a second plastic bag which is watertight, transparent and thin and the rear end of which is sealed, and the outer pipe of the injector is inserted in a given length into a uterus of a domestic animal in a state that an overlapped portion of both transparent plastic bags is sealed through a banding means, then the first plastic bag is moved relatively to the outer pipe to break a sealed portion of the front end of the first plastic bag, thereafter the flexible tube is picked with fingertips from outside of said second plastic bag, thereby pushing to send forward the flexible tube.